#!/usr/bin/perl -w
#-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
#
#  This program creates a fade (a sequence of frames) between two images.
#
#  Author:     Wesley C. Barris
#              AHPCRC
#              Minnesota Supercomputer Center, Inc.
#  Date:       January 7, 1994
#
#  Converted to perl and renamed from pbmfade to ppmfade by Bryan Henderson
#  on March 31, 2000 for inclusion in Netpbm.  Also, superfluous ability to 
#  process other formats removed.
#
#  Copyright @ 1994, Minnesota Supercomputer Center, Inc.
#
#  RESTRICTED RIGHTS LEGEND
#
#  Use, duplication, or disclosure of this software and its documentation
#  by the Government is subject to restrictions as set forth in subdivision
#  { (b) (3) (ii) } of the Rights in Technical Data and Computer Software
#  clause at 52.227-7013.
#
#-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
use strict;
use File::Temp "tempdir";


my $SPREAD =  1;
my $SHIFT =   2;
my $RELIEF =  3;
my $OIL =     4;
my $EDGE =    5;
my $BENTLEY = 6;
my $BLOCK =   7;
my $MIX =     8;
#
#  Set some defaults.
#
my $nframes = 30;			# total number of files created (1 sec)
my $first_file = "undefined";
my $last_file = "undefined";
my $base_name = "fade";		# default base name of output files
my $image = "ppm";		# default output storage format
my $mode = $SPREAD;		# default fading mode
#
#  Check those command line args.
#
if (@ARGV == 0) {
    usage();
}

my $n;  # argument number

for ($n = 0; $n < @ARGV; $n++) {
    if ("$ARGV[$n]" eq "-f") {
        $n++;
        $first_file = $ARGV[$n];
        if (-e $first_file) {
        } else {
            print "I can't find $first_file\n";
            exit 20;
        }
    } elsif ($ARGV[$n] eq "-l") {
        $n++;
        $last_file = $ARGV[$n];
        if (-e $last_file) {
        } else {
            print "I can't find $last_file\n";
            exit 20;
        }
    } elsif ($ARGV[$n] eq "-base") {
        $n++;
        $base_name = $ARGV[$n];
    } elsif ($ARGV[$n] eq "-spread") {
        $mode = $SPREAD;
    } elsif ($ARGV[$n] eq "-shift") {
        $mode = $SHIFT;
    } elsif ($ARGV[$n] eq "-relief") {
        $mode = $RELIEF;
    } elsif ($ARGV[$n] eq "-oil") {
        $mode = $OIL;
    } elsif ("$ARGV[$n]" eq "-edge") {
        $mode = $EDGE;
    } elsif ("$ARGV[$n]" eq "-bentley") {
        $mode = $BENTLEY;
    } elsif ("$ARGV[$n]" eq "-block") {
        $mode = $BLOCK;
    } elsif ("$ARGV[$n]" eq "-mix") {
        $mode = $MIX;
    } elsif ($ARGV[$n] eq "-help" || $ARGV[$n] eq "-h") {
        usage();
    } else {
        print "Unknown argument: $ARGV[$n]\n";
        exit 100;
    } 
}
#
#  Define a couple linear ramps.
#
# We don't use element 0 of these arrays.
my @spline10 = (0, 0, 0.11, 0.22, 0.33, 0.44, 0.55, 0.66, 0.77, 0.88, 1.0);
my @spline20 = (0, 0, 0.05, 0.11, 0.16, 0.21, 0.26, 0.32, 0.37, 0.42, 0.47, 
                0.53, 0.58, 0.63, 0.69, 0.74, 0.79, 0.84, 0.89, 0.95, 1.0);
#
#  Just what are we supposed to do?
#
my ($height, $width);    # width and height of our frames
if ($first_file ne "undefined") {
    if ((`pnmfile $first_file` =~ m{\b(\d+)\sby\s(\d+)} )) { 
        $width = $1; $height = $2;
    } else {
        print("Unrecognized results from pnmfile on $first_file.\n");
        exit(50);
    }
} elsif ($last_file ne "undefined") {
    if ((`pnmfile $last_file` =~ m{\b(\d+)\sby\s(\d+)} )) { 
        $width = $1; $height = $2;
    } else {
        print("Unrecognized results from pnmfile on $first_file.\n");
        exit(50);
    }
} else {
    print("ppmfade:  You must specify -f or -l (or both)\n");
    exit(90);
}

print("Frames are " . $width . "W x " . $height . "H\n");

#
# We create a tmp-directory right here
#
my $tempdir = tempdir("ppmfade.XXXXXXX", CLEANUP => 1);

if ($first_file eq "undefined") {
    print "Fading from black to ";
    system("ppmmake \\#000 $width $height >$tempdir/junk1.ppm");
} else {
    print "Fading from $first_file to ";
    system("cp", $first_file, "$tempdir/junk1.ppm");
}

if ($last_file eq "undefined") {
    print "black.\n";
    system("ppmmake \\#000 $width $height >$tempdir/junk2.ppm");
} else {
    print "$last_file\n";
    system("cp", $last_file, "$tempdir/junk2.ppm");
}

#
#  Perform the fade.
#

# Here's what our temporary files are:
#   junk1.ppm: The original (fade-from) image
#   junk2.ppm: The target (fade-from) image
#   junk3.ppm: The frame of the fade for the current iteration of the 
#                the for loop.
#   junk1a.ppm: If the fade involves a ppmmix sequence from one intermediate
#                 image to another, this is the first frame of that 
#                 sequence.
#   junk2a.ppm: This is the last frame of the above-mentioned ppmmix sequence

my $i;    # Frame number
for ($i = 1; $i <= $nframes; $i++) {
    print("Creating $i of $nframes...\n");
    if ($mode eq $SPREAD) {
        if ($i <= 10) {
            my $n = $spline20[$i] * 100;
            system("ppmspread $n $tempdir/junk1.ppm >$tempdir/junk3.ppm");
        } elsif ($i <= 20) {
            my $n;
            $n = $spline20[$i] * 100;
            system("ppmspread $n $tempdir/junk1.ppm >$tempdir/junk1a.ppm");
            $n = (1-$spline20[$i-10]) * 100;
            system("ppmspread $n $tempdir/junk2.ppm >$tempdir/junk2a.ppm");
            $n = $spline10[$i-10];
            system("ppmmix $n $tempdir/junk1a.ppm $tempdir/junk2a.ppm >$tempdir/junk3.ppm");
        } else {
            my $n = (1-$spline20[$i-10])*100;
            system("ppmspread $n $tempdir/junk2.ppm >$tempdir/junk3.ppm");
        }
    } elsif ($mode eq $SHIFT) {
        if ($i <= 10) {
            my $n = $spline20[$i] * 100;
            system("ppmshift $n $tempdir/junk1.ppm >$tempdir/junk3.ppm");
        } elsif ($i <= 20) {
            my $n;
            $n = $spline20[$i] * 100;
            system("ppmshift $n $tempdir/junk1.ppm >$tempdir/junk1a.ppm");
            $n = (1-$spline20[$i-10])*100;
            system("ppmshift $n $tempdir/junk2.ppm >$tempdir/junk2a.ppm");
            $n = $spline10[$i-10];
            system("ppmmix $n $tempdir/junk1a.ppm $tempdir/junk2a.ppm >$tempdir/junk3.ppm");
        } else {
            my $n = (1-$spline20[$i-10]) * 100;
            system("ppmshift $n $tempdir/junk2.ppm >$tempdir/junk3.ppm");
        }
    } elsif ($mode eq $RELIEF) {
        if ($i == 1) {
            system("ppmrelief $tempdir/junk1.ppm >$tempdir/junk1r.ppm");
        }
        if ($i <= 10) {
            my $n = $spline10[$i];
            system("ppmmix $n $tempdir/junk1.ppm $tempdir/junk1r.ppm >$tempdir/junk3.ppm");
        } elsif ($i <= 20) {
            my $n = $spline10[$i-10];
            system("ppmmix $n $tempdir/junk1r.ppm $tempdir/junk2r.ppm >$tempdir/junk3.ppm");
        } else {
            my $n = $spline10[$i-20];
            system("ppmmix $n $tempdir/junk2r.ppm $tempdir/junk2.ppm >$tempdir/junk3.ppm");
        }
        if ($i == 10) {
            system("ppmrelief $tempdir/junk2.ppm >$tempdir/junk2r.ppm");
        }
    } elsif ($mode eq $OIL) {
        if ($i == 1) {
            system("ppmtopgm $tempdir/junk1.ppm | pgmoil >$tempdir/junko.ppm");
            system("rgb3toppm $tempdir/junko.ppm $tempdir/junko.ppm $tempdir/junko.ppm " .
                   ">$tempdir/junk1o.ppm");
        }
        if ($i <= 10) {
            my $n = $spline10[$i];
            system("ppmmix $n $tempdir/junk1.ppm $tempdir/junk1o.ppm >$tempdir/junk3.ppm");
        } elsif ($i <= 20) {
            my $n = $spline10[$i-10];
            system("ppmmix $n $tempdir/junk1o.ppm $tempdir/junk2o.ppm >$tempdir/junk3.ppm");
        } else {
            my $n = $spline10[$i-20];
            system("ppmmix $n $tempdir/junk2o.ppm $tempdir/junk2.ppm >$tempdir/junk3.ppm");
        }
        if ($i == 10) {
            system("ppmtopgm $tempdir/junk2.ppm | pgmoil >$tempdir/junko.ppm");
            system("rgb3toppm $tempdir/junko.ppm $tempdir/junko.ppm $tempdir/junko.ppm " .
                   ">$tempdir/junk2o.ppm");
        }
    } elsif ($mode eq $EDGE) {
        if ($i == 1) {
            system("ppmtopgm $tempdir/junk1.ppm | pgmedge >$tempdir/junko.ppm");
            system("rgb3toppm $tempdir/junko.ppm $tempdir/junko.ppm $tempdir/junko.ppm " .
                   ">$tempdir/junk1o.ppm");
        }
        if ($i <= 10) {
            my $n = $spline10[$i];
            system("ppmmix $n $tempdir/junk1.ppm $tempdir/junk1o.ppm >$tempdir/junk3.ppm");
        } elsif ($i <= 20) {
            my $n = $spline10[$i-10];
            system("ppmmix $n $tempdir/junk1o.ppm $tempdir/junk2o.ppm >$tempdir/junk3.ppm");
        } else {
            my $n = $spline10[$i-20];
            system("ppmmix $n $tempdir/junk2o.ppm $tempdir/junk2.ppm >$tempdir/junk3.ppm");
        }
        if ($i == 10) {
            system("ppmtopgm $tempdir/junk2.ppm | pgmedge >$tempdir/junko.ppm");
            system("rgb3toppm $tempdir/junko.ppm $tempdir/junko.ppm $tempdir/junko.ppm " .
                   ">$tempdir/junk2o.ppm");
        } 
    } elsif ($mode eq $BENTLEY) {
        if ($i == 1) {
            system("ppmtopgm $tempdir/junk1.ppm | pgmbentley >$tempdir/junko.ppm");
            system("rgb3toppm $tempdir/junko.ppm $tempdir/junko.ppm $tempdir/junko.ppm " .
                   ">$tempdir/junk1o.ppm");
        }
        if ($i <= 10) {
            my $n = $spline10[$i];
            system("ppmmix $n $tempdir/junk1.ppm $tempdir/junk1o.ppm >$tempdir/junk3.ppm");
        } elsif ($i <= 20) {
            my $n = $spline10[$i-10];
            system("ppmmix $n $tempdir/junk1o.ppm $tempdir/junk2o.ppm >$tempdir/junk3.ppm");
        } else {
            my $n = $spline10[$i-20];
            system("ppmmix $n $tempdir/junk2o.ppm $tempdir/junk2.ppm >$tempdir/junk3.ppm");
        }
        if ($i == 10) {
            system("ppmtopgm $tempdir/junk2.ppm | pgmbentley >$tempdir/junko.ppm");
            system("rgb3toppm $tempdir/junko.ppm $tempdir/junko.ppm $tempdir/junko.ppm " .
                   ">$tempdir/junk2o.ppm");
        }
    } elsif ($mode eq $BLOCK) {
        if ($i <= 10) {
            my $n = 1 - 1.9*$spline20[$i];
            system("pnmscale $n $tempdir/junk1.ppm | " .
                   "pnmscale -width $width -height $height >$tempdir/junk3.ppm");
        } elsif ($i <= 20) {
            my $n = $spline10[$i-10];
            system("ppmmix $n $tempdir/junk1a.ppm $tempdir/junk2a.ppm >$tempdir/junk3.ppm");
        } else {
            my $n = 1 - 1.9*$spline20[31-$i];
            system("pnmscale $n $tempdir/junk2.ppm | " .
                   "pnmscale -width $width -height $height >$tempdir/junk3.ppm");
        }
        if ($i == 10) {
            system("cp", "$tempdir/junk3.ppm", "$tempdir/junk1a.ppm");
            system("pnmscale $n $tempdir/junk2.ppm | " .
                   "pnmscale -width $width -height $height >$tempdir/junk2a.ppm");
        }    
    } elsif ($mode eq $MIX) {
        my $fade_factor = sqrt(1/($nframes-$i+1));
        system("ppmmix $fade_factor $tempdir/junk1.ppm $tempdir/junk2.ppm >$tempdir/junk3.ppm");
    } else {
        print("Internal error: impossible mode value '$mode'\n");
    }

    my $outfile = sprintf("%s.%04d.ppm", $base_name, $i);
    system("cp", "$tempdir/junk3.ppm", $outfile);
}


# The temporary files are automatically deleted

exit(0);



sub usage() {
   print "Usage: ppmfade [-f first_file] [-l last_file]\n";
   print "               [-spread|-relief|-oil|-edge|-bentley|-block]\n";
   print "               [-base basename]\n";
   print "Notes: Default base: fade\n";
   print "       The resulting image files will be named fade.NNNN.ppm.\n";
   exit(100);
}